Scientists have good estimates of where the receding ground line is, thanks to satellites tracking tiny changes in ice height. But they didn’t have a good picture of what a glacier’s stomach looks like on the ground line because it’s under thousands of feet of ice. “These data are really interesting because we are looking into a hidden system,” says University of Waterloo glaciologist Christine Doe, who studies Antarctic glaciers but was not involved in the research.
With Icefin, the researchers were able to remotely control the camera, measuring the salinity, temperature, and oxygen content of the water. “We saw that the ice base itself has a very complex topography, so there are a lot of stairs, terraces, cracks and cracks,” says British Antarctic Survey physical oceanographer Peter Davies, lead author of one of the papers and co-author of the study. another. “The rate of melting on different surfaces was very different.”
Where the underside of the glacier (or basal ice, in scientific terms) is smoother, melting is definitely occurring, but much more slowly than where the topography is uneven. This is because a layer of cold water lies where the ice is flat, insulating it from the warmer ocean water like a liquid blanket. But where the relief is sloping and uneven, there are more vertical surfaces where warm water can attack the ice, including from the side. This melting creates a kind of “scalloped” appearance, like the surface of a golf ball.
These complex expanding basal elements may then have influenced the rest of the ice. “If you open objects under the ice, you also get reflections on the surface due to the way the ice floats,” says Davis. “Therefore, there is concern that if you widen these faults and crevices under the ice, you could destabilize the ice shelf, which could lead to even more destruction over time.”